1. Field of the Invention
The present invention relates to an apparatus and program for transmitting data, for instance which is suitable for transmitting image data, which is data related to an image, to an image forming apparatus such as an inkjet recording apparatus.
2. Description of Related Art
The resolution of an image recorded by an inkjet recording apparatus or an inkjet printer is getting higher and higher, which leads to increase in an amount of image data handled by the inkjet printer. On the other hand, there is a demand for reducing a time necessary to transmit image data to an inkjet printer of high print rate, such as those having an inkjet head of line type extending across a width of a recording medium, i.e., extending perpendicular to a medium feed direction. To meet this demand, it is known to compress image data and transmit the compressed data to the inkjet printer, thereby reducing an amount of data transmission and accordingly the time necessary to transmit image data.
The image data handled by the inkjet printer is formed as a sequence of a plurality data elements of a plurality of kinds, and each data element corresponds to one of image dots. More specifically, each data element represents, by a bit sequence made up of a plurality of bits, an amount of ink to be ejected for forming (or not forming) the corresponding image dot. It does not often occur that consecutive two or more bits in a bit sequence take a same value. Thus, in image data, a frequency of occurrence of two adjacent bits having different values is high, resulting in decrease in the efficiency of compressing the image data. This in turn increases time necessary for data transmission.
There has been described the case where image data is transmitted to an inkjet printer. However, the same disadvantage can occur in other types of printers, as well as an apparatus for transmitting image data in order to form an image on a screen of a display device on the basis thereof. Further, some apparatuses for transmitting data other than image data may suffer from the disadvantage.